1. Field of the Invention
The present invention relates to a method of uniforming physical random numbers, in which physical random numbers can be simply uniformed.
Further, the present invention relates to a physical random number generation device suitable for various uses, in which the specific uses include security, encryption, authentication, locking, coded communication, smart cards (e.g., electronic money, credit card, consultation ticket), home security, car security, keyless entry, probability, lottery, game, amusements (e.g., pinball, slot machine), simulations (e.g., Monte Carlo in meteorological or scientific computation or stock price), graphics (e.g., CG, automatic composition), control, measurement, FA, and robot control (artificial intelligence).
2. Description of the Related Art
Generally, random numbers include a pseudo-random number deterministically generated by computation and a physical random number generated using a physical phenomenon in the natural world. The latter (physical random number) is generated based on a random phenomenon in a true meaning and has a disposition of an ideal random number. However, when physical random numbers are actually generated, various error factors intervene in the intermediate process, and the ideal random number is not necessarily output, possibly producing the deviated random number. The error factors include a width of clock for reference in making the digitization and a mixed excess noise in using the noise.
As a conventional method for improving a deviation in the physical random numbers, or as a conventional method for uniforming the physical random numbers, a Neumann collector for improving a deviation in the random numbers, employing two binary random numbers (e.g., refer to “non-patent document” stated below), and a method for improving a deviation in the physical random numbers by synthesizing the physical random numbers generated based on the noise with the pseudo-random numbers (herein after referred to as a random number synthesis method) were proposed (e.g., refer to Japanese Patent Laid-Open No. 2001-344094, paragraphs [0014] to [0018] and FIG. 1, and non-patent document, Benjamin Jun and Paul Kocher, “The Intel Random Number Generator”, CRYPTOGRAPHY RESEARCH, published on 1999.4.22 (page 4, 4.3. Digital Post-Processing)).
However, the Neumann collector has a drawback that the generation rate of random number is decreased, because two-bit random numbers are required to output one-bit random numbers, and there is the chance of not outputting random numbers depending on the combination of two bits.
Also, the random number synthesis method has an inconvenience of letting others recognize the deviation of random numbers and lacking the safety, because, if the pseudo-random number is known, then the physical random number as a basis can be taken out of the output.
Most conventional physical random number generation devices as previously described employ the noise occurring in a semiconductor, in which some are connected to the personal computer from the outside and have large size and some generate the random numbers in an IC chip simplex. For amusements, when a temporally random signal occurs, the random number may be given by referring to the value of a high speed counter provided.
Generally, it is difficult for the physical random number generator to generate random numbers at high rate, and a large amount of random numbers may be often required beyond the random number generating rate. Therefore, it is considered that a storage medium is provided to store random numbers, or the amount of generating the random numbers is increased, employing a plurality of physical random number generation devices, although it is necessary for the user to construct a complex circuit to realize this.
Also, generally, the physical random number may possibly change the quality of the random number depending on the use environment, but it is beneficial that the user checks whether or not the random number generated by the physical random number generation device is usable as the genuine random number. However, to test the random numbers, a dedicated measuring apparatus must be constructed, and it is difficult for the general user of the physical random number generation device to accept such an operation taking excess cost and trouble. Since the testing of random numbers deals with a large amount of data, the storage device storing it needs a large capacity, and it takes a lot of time to perform a computation processing for testing.
Moreover, the conventional physical random number generation device is well known to have a physical random number generator comprising a phase adjuster having two delays and a selector, and a physical random number generator having a flip-flop and a feedback circuit, as disclosed in Japanese Patent Laid-Open No. 2003-29964, for example.
However, this conventional physical random number generation device requires two delays and the selector corresponding to two systems of signal line inputted into a clock terminal and a data terminal of the flip-flop, leading to an inconvenience that the scale of the phase adjuster or the physical random number generator is increased, the occupancy area is expanded, and the consumption power is increased. Especially when the physical random number generator is mixed in an IC (Integrated Circuit) with a lot of functions of CPU (Central Processing Unit), ROM (read only memory), and RAM (random access memory), it is strongly demanded that the occupancy area of the physical random number generator is reduced.